1. Field Of The Invention
The invention relates to an agent for the pickling of and as an antioxidant for workpieces made of iron and/or steel which are subjected to non-cutting, hot transformation.
2. Prior Art
In the case of the production of metal sheets by rolling, of profiles in profile rollers or of seamless pipes on push-bench plants, Assel mills, plug mills, continuous mills, hot pilger mills or multiple pipe mill installations, up-setters and extrusion presses, the surfaces which are processed, for example, in the case of hollow blocks, blooms or pipes such as the inside wall surfaces of pipes, must be pickled prior to rolling in order to keep the abrasion of the tools within limits and in order to impart a good surface characteristic to the developing workpiece.
According to the experience of the art, a smooth surface can be achieved whenever the workpiece has been descaled or pickled prior to transformation. The pickling can be accomplished mechanically or with the help of pickling baths, for example, baths of sodium hydroxide. Also solid pickling agents consisting of mixtures of sodium sulfate and phosphoric acid have already been used. An additional proposal provided for the removal of scale by the application of a melting fluid mixture of sodium silicate and soda with borax or phosphates which upon cooling are supposed to break off the scale from the surface of the workpiece.
All of these processes and the descaling and pickling agents used therefor, however, are not capable of fulfilling the requirements which are made of the pickling agents, especially in an installation for the production of seamless pipes, but also in modern rolling or profile rolling installations. For example, in the case of the production of seamless pipes in the previously mentioned installations, the pickling agent must be applied and evenly distributed in the hollow space of the workpiece, which is at rolling temperature, within the operating rhythm (cycles), with the time intervals between two tubes being 15 to 180 seconds and the time necessary to introduce the product into the shell being 1 to 2 seconds, whereby a quick and reliable pickling is to be achieved in order that then immediately following such step the workpiece can be rolled out.
U.S. Pat. No. 4,039,337 (Brown et al.) discloses an aqueous dispersion which is used for release and parting in glass-forming operations. The aqueous dispersion contains a solid lubricant, a water-soluble silicate binder, a settling agent and a water-soluble phosphate.